The invention relates to an electric arc detection device comprising measuring means for measuring an AC current and an AC voltage, and analyzing means connected to the measuring means. The analyzing means compute an integral of an absolute value of the AC current over at least one mains half-wave, at the rhythm of a sequencing signal, and supply a current integration signal. Said means also compute an integral of an absolute value of the AC voltage over at least one mains half-wave and supply a voltage integration signal. The analyzing means comprise differentiation means supplying a current differential signal representative of the difference between a first current integration signal and a second current integration signal measured over a period before said first integration signal. The differentiation means also supply a differential voltage signal representative of the difference between a first voltage integration signal and a second voltage integration signal measured over a period before said first integration signal. The electric arc detection device further comprises decision-making means connected to the analyzing means and designed to send at least one trip signal.
The invention also relates to a switchgear device comprising one such electric arc detection device and to a method for detecting an electric arc. The method for detecting an electric arc comprises measurement of an AC current and an AC voltage by means of measuring means, computation at the rhythm of a sequencing signal of an integral of an absolute value of the AC current and of the AC voltage over at least one mains half-wave and of a current integration signal and a voltage integration signal. The method for detecting an electric arc comprises supply of a current differential signal representative of the difference between a first current integration signal and a second current integration signal measured over a period before said first integration signal and supply of a differential voltage signal representative of the difference between a first voltage integration signal and a second voltage integration signal measured over a period before said first integration signal.